MATH GWD-TT-30-Q9&Q18

随机抽取的居然是第30套，貌似讨论不多……有两道题想确认下：

Q9:

Is the measure of one of the interior angles of quadrilateral ABCD equal to 60 degrees?

(1)   Two of the interior angles of ABCD are right angles.

(2) The degree measure of angle ABC is twice the degree measure of angle BCD.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

答案是C，但我认为是E，理由是可能组合90，90，60，120，也可能45，90，90，135，不确定

Q18:

If k is a positive integer, is k the square of an integer?

(1)   k is divisible by 4.

(2) k is divisible by exactly 4 different prime numbers.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

答案：E

(2)到底是什么意思？我的理解是K刚好被4个不同的质数整除，也就是说，K只包含4个不同的质因数，无其他因子，那怎么会是E，不应该是B么？K不可能是某个数的平方阿~

第一题你是正确的,应该选E.

第二题中条件(2)意思是:k分解质因子后,只有4个不同的数字,但是没个质数有几次方并不知道.例如 2*(3^2)*(5^3)*(7^4),所以选E.

thx!